Professional
Technical
IVT
BOLD signal
Also written as: BOLD — Blood Oxygen Level-Dependent
Blood oxygen level-dependent signal used in functional MRI to detect brain activity based on hemodynamic changes.
Full Definition
Blood oxygen level-dependent (BOLD) signal is the fundamental contrast mechanism in functional magnetic resonance imaging (fMRI). It measures changes in blood oxygenation that occur in response to neural activity, as active brain regions consume more oxygen and experience increased blood flow. The BOLD signal forms the basis for mapping brain function and connectivity patterns in both clinical and research neuroimaging.
Usage
Usage note: Often written as 'BOLD signal' rather than just 'BOLD' to clarify the measured parameter.
In Context
- "The BOLD signal demonstrated increased activation in the motor cortex during the hand-tapping task." — fMRI report
- "Reduced BOLD signal variability was observed in patients with autism spectrum disorders." — research publication
Also known as
BOLD contrast
hemodynamic signal
Don't confuse with
BOLD imaging
BOLD sequence